1. Field of the Invention
An automotive heat, ventilation and air conditioning (HVAC) system including an electrical control module having a circuit board in the air flow.
2. Description of the Prior Art
The electrical control module employed in HVAC systems are usually resistor devices for controlling the blower motor and are disposed so as to extend into an air passage defined by housing, the blower motor being supported in the housing. The electrical control module comprises a base supported by the housing and a circuit board having spaced side edges and extends into the housing from the base. An electrical circuit is disposed on the circuit board for controlling the motor. Such an electrical control module is shown in U.S. Pat Nos. 5,268,665 to Iwao and Des. 340,223 to Nitta et al.
The known electrical control modules typically include a screen-printed resistance circuit on a rectangular shaped circuit board. The circuit board is disposed in the air flow path in a passage in the HVAC housing to dissipate heat and, sometimes, whistles and noises are generated by the air moving over the circuit board. In addition, the length of the rectangular shape to achieve the circuit lengths increases packaging space thereby increasing shipping expenses.